Physics F=ma Help!!! 1. The problem statement, all variables and given/known data Ok so I'm supposed to present the solution of a problem to my AP Physics class tomorrow. The thing is, I don't understand the question at all!!! Here is the problem (easy) and the possible answer choices. How would I go about doing this??? A 150-N sled is pulled up a 28 degree slope at a constant speed by a force of 100N parallel to the hill. What force directed up the hill will allow the sled to move downhill at a constant speed? A) 181N B) 170N C) 130N D) 141N 2. Relevant equations F=ma F=uN (Not sure if I need) F(parallel) = W*sin(Theta) F(perpendicular) = W*cos(Theta) 3. The attempt at a solution Since the sled is moving up at a constant velocity, the summation of the forces would be 0. Thus the summation of the forces would be 100N - 150Nsin28 = 0. However, 100N - 150sin28 only yields 29.6N so I am assuming there is a frictional force of 29.6N. Thus I found the coefficient of friction to be 0.224 (but is that even relevant?). What I do not get is what the problem is asking. Can someone please clarify what it is specifically asking and what I would do to get that answer? Also, if you would be kind enough, can you post the answer so I have a target answer that I can work towards. (Don't worry about me cheating because my teacher requires me to show all work or she won't even bother to look at the question.) Thanks for all your help!